Ottawa Senators forward Jean-Gabriel Pageau will miss at least six months after tearing his Achilles tendon during a team fitness session on Thursday.

The Senators announced Friday Pageau underwent surgery on his right ankle Thursday and his timeline will sideline him until at least March.

The 25-year-old centre scored 14 goals and 15 assists over 78 games with the Sens in 2017-18, his sixth year with the club. He was expected to serve in the team's top-six this season.

Ottawa acquired centre Chris Tierney from the San Jose Sharks as part of their return for superstar defenceman Erik Karlsson on Thursday. He had 17 goals and 40 points in 82 games with the Sharks last season.

The Senators selected Pageau in the fourth round of the 2011 NHL Entry Draft. 

The Ottawa native is entering the second year of a three-year, $9.3 million contract.